Dielectrically-loaded multifilar antennas are disclosed in Published International Patent Application No. WO2006/136809, British Patent Publication No. 2442998A, European Patent Publication No. EP1147571A, British Patent Publications Nos. 2420230A, 2444388A, 2437998A and 2445478A. The entire disclosure of these patent publications is incorporated in the present application by reference. Such antennas are intended mainly for receiving circularly polarised signals from a Global Navigation Satellite System (GNSS), e.g. from satellites of the Global Positioning System (GPS) satellite constellation, for position fixing and navigation purposes. Other satellite-based services for which such antennas are useful include satellite telephone services such as the L-band Inmarsat service 1626.5-1675.0 MHz and 1518.0-1559.0 MHz, the TerreStar (registered trade mark) S-band service, the ICO Global Communications S-band service and the SkyTerra service. The S-band services have allocated frequency bands in the range of from 2000 MHz to 2200 MHz.